title: QuantiFERON to diagnose infection by Mycobacterium tuberculosis: performance in infants and older children.
abstract: OBJECTIVE
  QuantiFERON value to diagnose tuberculosis (TB) in young children remains to be clarified. To this aim QF-TB-IT performance was evaluated in a large series of immunocompetent children that were stratified according to age and clinical conditions.
  
  
  METHODS
  QF-TB-IT reactivity was analyzed in 226 immunocompetent children (0-15 years old): 31 were uninfected despite TB contact; 51 presented TB disease; 39 had Latent TB (LTBI) and 105 had TB disease suspected but an alternative diagnosis (TB excluded).
  
  
  RESULTS
  QF-TB-IT specificity was 100% in TB excluded. In TB disease, low sensitivity of QF-TB-IT in infants (40%) increased with aging (77% in 1-<5 years and 82% in 5-<15 years old subgroups). In LTBI, agreement between TST and QF-TB-IT was 0% in infants, 40% in 1-<5 years and 57% in children >5 years old. Finally, the incidence of indeterminate results was high (24%) in children <5 years old with TB excluded, especially with non-TB pneumonitis (61%), but was low (0-6%) regardless of age group in TB disease, LTBI and uninfected contact cases.
  
  
  CONCLUSIONS
  In our low burden country, i) QF-TB-IT specificity was 100%, ii) QF-TB-IT sensitivity was low in infants but commensurable to adult values in older children, and iii) indeterminate results mostly relied on ongoing infections unrelated to TB.
authors.affiliation: Laboratory of Immunology, Robert Debré Hospital, 48 Boulevard Sérurier, 75019 Paris, France; Assistance Publique-Hôpitaux de Paris (AP-H), Univ. Paris Diderot, Sorbonne Paris Cité, Paris, France.
authors.forename: Adeline
authors.initials: A
authors.lastname: Blandinières
authors.forename: Agathe
authors.initials: A
authors.lastname: de Lauzanne
authors.forename: Valérie
authors.initials: V
authors.lastname: Guérin-El Khourouj
authors.forename: Nadège
authors.initials: N
authors.lastname: Gourgouillon
authors.forename: Hélène
authors.initials: H
authors.lastname: See
authors.forename: Béatrice
authors.initials: B
authors.lastname: Pédron
authors.forename: Albert
authors.initials: A
authors.lastname: Faye
authors.forename: Ghislaine
authors.initials: G
authors.lastname: Sterkers
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D059425:Interferon-gamma Release Tests / Q000379:methods*; D055985:Latent Tuberculosis / Q000175:diagnosis; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis*
keywords: Cytokines; Infants; Interferon-gamma release assay; Tuberculosis